This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics magazine. The source must be symmetrical. The capacitors can be changed for other frequencies.
We found this circuit in the March 1992 issue of Radio Electronics magazine. The circuit has a...
The circuit presented may use any general purpose transistor. The indicator is an LED and...
This unusual audio amplifier configuration was obtained in a 1974 documentation. The PNP...